Nokia has issued a thinly-veiled threat to Google and Asus, the makers of the new Nexus 7 Android tablet, by claiming that the device infringes its patents and recommending that the two companies "simply approach" the handset maker for a patent license.

Investment company Moody's became the last of the big-three credit-rating firms to downgrade Nokia to junk status on Friday, serving the Finnish phone maker yet another blow as it struggles to survive amidst a surging smartphone market.

Apple continues to gain share in the worldwide smartphone market, as the latest data shows the iOS mobile operating system accounted for nearly a quarter of all smartphones shipped in the first quarter of 2012.

Despite strong growth year-over-year, Apple ceded its spot as the world's top smartphone vendor in the first quarter of 2012 as Samsung boosted both smartphone and feature phone shipments to record levels.

After Samsung confirmed record earnings for the March quarter on Friday, a set of new analyses estimate that the company overtook Apple to become the world's largest smartphone vendor while simultaneously passing long-time leader Nokia for the top spot among global mobile phone vendors.

After Microsoft was found to be making more from licensing its patents to Android handset makers than from selling its own Windows Phone 7, it's now clear Nokia has earned more from licensing patents to Apple than it has selling its own Lumia Windows Phone 7 devices.